CSL373/CSL633 Major Exam Operating Systems Sem II, May 6, 2013 Answer all 8 questions Max. Marks: 56
|
|
- Adelia Harmon
- 6 years ago
- Views:
Transcription
1 CSL373/CSL633 Major Exam Operating Systems Sem II, May 6, 2013 Answer all 8 questions Max. Marks: True or False. Give reasons and/or brief explanation. No marks for incomplete/wrong explanation. a. On xv6, the walkpgdir() function gets executed on every memory access by the user process. [1 mark] b. For most desktop applications, using huge pages (e.g., 2GB pages) will result in better overall system performance. [1 mark] c. An in memory filesystem, RAMFS, as discussed in the xsyncfs paper, will always have better performance than any on disk filesystem for a disk intensive benchmark. [1 mark]
2 d. In a ext3 journaling file system, a transaction can be closed at any time. [2.5 marks] e. In xv6, a file create can fail even if the disk is not full. [2 marks]
3 f. On a FAT32 filesystem, corruption of one disk block could potentially lead to the loss of complete file data. [2 marks] g. The best possible filesystem layout for a read only filesystem (which is written only once in the beginning) is contiguous allocation. Explain why or why not. [2.5 marks]
4 h. When using a write through buffer cache, one does not need to worry about the order of disk writes (from a filesystem consistency perspective across power reboots). Explain why or why not. [2 marks] i. The First Fit algorithm is used when allocating pages to processes. [1 mark]
5 2. In xv6, the kernel stack (kstack) of a process is limited by KSTACKSIZE (4096 bytes). List at least three invariants that the kernel maintains to ensure that kstack never overflows. i.e., if one of those invariants is violated, kstack could potentially overflow. [5 marks]
6 3. The L 1 cache of a processor could either be physically indexed (i.e., indexed using physical addresses), or virtually indexed (i.e., indexed using virtual addresses). List the primary advantage of using a virtually addressed L1 cache. List the primary advantage of a physically addressed L1 cache. [3 marks]
7 4. Professor X really liked the xsyncfs paper, but found it a bit incomplete. He suggests that external synchrony should be implemented over a cluster of machines, to achieve its real potential. He is developing a new filesystem called networked externally synchronous file system, or nxsyncfs. In nxsyncfs, an output is not considered external, until it leaves to the external network. In other words, all communication between two hosts within the cluster is considered internal. Assuming that a cluster of machines can only be observed through the external network interface (assume there is no console access to these machines), answer the following questions: i. What will be your filesystem sync policy on nxsyncfs? i.e., when will you insert fsync calls? Does nxsyncfs give more optimization opportunities over xsyncfs? Briefly explain. [2 marks]
8 ii. What kind of data structures and mechanisms will you need to implement for nxsyncfs? Assume that all xsyncfs mechanisms are already in place. Only emphasize the extra structures and mechanisms that you will need to add over xsyncfs, to take advantage of nxsyncfs semantics? [3 marks]
9 iii. Give an example of an application that will show significant improvements with nxsyncfs over xsyncfs. i.e., the performance of the application should significantly improve if nxsyncfs is used in place of xsyncfs. [3 marks]
10 5. Producer consumer with semaphores Consider the following functions, produce(item), and consume() for a shared queue, shared between multiple producers and multiple consumers. As discussed in class, semaphores are used to synchronize access to this shared queue. void produce (item): sema_down(mutex); sema_down(holes); insert_item(item, buffer); sema_up(items); sema_up(mutex); item consume(void): sema_down(mutex); sema_down(items); item = remove_item(buffer); sema_up(holes); sema_up(mutex); In this code, the semaphore mutex is used for mutual exclusion, semaphore holes is used to count the number of empty slots in the buffer, and semaphore items is used to count the number of items in the buffer. a. What should be the initial values of the semaphores mutex, holes, and items? Assume that the buffer size is N. [1.5 marks]
11 b. Look at this code closely and answer if this code is correct. If you think it is correct, briefly explain the invariants that prove it correct. If you think it is incorrect, explain why and fix it so that it becomes correct (with brief explanation as before). [4.5 marks]
12 6. Consider the ext3 journaling filesystem. Answer the following questions: a. How does ext3 ensure a low runtime overhead, even though a disk write results in at least two separate disk writes (one to log, and one to FS tree). [1.5 marks] b. Consider a situation where filesystem compound transaction X has started committing. What happens to the transactions (or atomic operations) that are already ongoing? Do the updates of those operations get reflected in the next compound transaction (say transaction Y), or do they get reflected in the previous transaction (transaction X)? [2 marks] c. What happens to the operations that were started after transaction X started committing but before the commit record was written? Do the updates by these operations get reflected in the previous transaction (transaction X) or the next transaction (transaction Y)? [2 marks]
13 d. While transaction X is committing (i.e., commit record has not yet been written), what happens if some operation in transaction Y writes to a disk block which is also a part of transaction X? How does ext3 ensure correct behaviour? [3.5 marks]
14 7. Implement reader writer locks using spinlocks and sleep/wakeup. You must not use any other synchronization mechanism. You should also not assume specific architecture instructions like xchg, etc. Your implementation should be efficient. No scheduling requirements: The scheduling of read/write locks can be arbitrary, i.e., if a reader (potentially many) and a writer are both waiting for a lock, any one can win. Also, if a lock is being held in read mode, other readers may be allowed to acquire it, even if a writer is waiting. You have to implement: struct rwlock, read_acquire(), read_release(), write_acquire(), write_release() functions. You are allowed to use: spinlock_acquire(), spinlock_release(), sleep(), wakeup(). [4 marks]
15
16 8. Security: Explain how submit pintos script is able to both write to my (sbansal s) home as well as to your (the person who is submitting) home. [3 marks]
17 9. How does an OS detect Thrashing? [1.5 marks]. How does it deal with it? [1.5 marks]
CSL373/CSL633 Major Exam Solutions Operating Systems Sem II, May 6, 2013 Answer all 8 questions Max. Marks: 56
CSL373/CSL633 Major Exam Solutions Operating Systems Sem II, 2012 13 May 6, 2013 Answer all 8 questions Max. Marks: 56 1. True or False. Give reasons and/or brief explanation. No marks for incomplete/wrong
More informationPROJECT 6: PINTOS FILE SYSTEM. CS124 Operating Systems Winter , Lecture 25
PROJECT 6: PINTOS FILE SYSTEM CS124 Operating Systems Winter 2015-2016, Lecture 25 2 Project 6: Pintos File System Last project is to improve the Pintos file system Note: Please ask before using late tokens
More informationCSE 451: Operating Systems Winter Lecture 7 Synchronization. Steve Gribble. Synchronization. Threads cooperate in multithreaded programs
CSE 451: Operating Systems Winter 2005 Lecture 7 Synchronization Steve Gribble Synchronization Threads cooperate in multithreaded programs to share resources, access shared data structures e.g., threads
More informationFinal Exam Preparation Questions
EECS 678 Spring 2013 Final Exam Preparation Questions 1 Chapter 6 1. What is a critical section? What are the three conditions to be ensured by any solution to the critical section problem? 2. The following
More informationSynchronization COMPSCI 386
Synchronization COMPSCI 386 Obvious? // push an item onto the stack while (top == SIZE) ; stack[top++] = item; // pop an item off the stack while (top == 0) ; item = stack[top--]; PRODUCER CONSUMER Suppose
More informationCSE 451: Operating Systems Winter Lecture 7 Synchronization. Hank Levy 412 Sieg Hall
CSE 451: Operating Systems Winter 2003 Lecture 7 Synchronization Hank Levy Levy@cs.washington.edu 412 Sieg Hall Synchronization Threads cooperate in multithreaded programs to share resources, access shared
More information2 nd Half. Memory management Disk management Network and Security Virtual machine
Final Review 1 2 nd Half Memory management Disk management Network and Security Virtual machine 2 Abstraction Virtual Memory (VM) 4GB (32bit) linear address space for each process Reality 1GB of actual
More informationOperating Systems (1DT020 & 1TT802)
Uppsala University Department of Information Technology Name: Perso. no: Operating Systems (1DT020 & 1TT802) 2009-05-27 This is a closed book exam. Calculators are not allowed. Answers should be written
More informationAdvanced file systems: LFS and Soft Updates. Ken Birman (based on slides by Ben Atkin)
: LFS and Soft Updates Ken Birman (based on slides by Ben Atkin) Overview of talk Unix Fast File System Log-Structured System Soft Updates Conclusions 2 The Unix Fast File System Berkeley Unix (4.2BSD)
More informationOperating Systems. Synchronization
Operating Systems Fall 2014 Synchronization Myungjin Lee myungjin.lee@ed.ac.uk 1 Temporal relations Instructions executed by a single thread are totally ordered A < B < C < Absent synchronization, instructions
More informationCOL331/COL633 Major Exam Operating Systems Sem II, Answer all 14 questions (12 pages) Max. Marks: 41
1 COL331/COL633 Major Exam Operating Systems Sem II, 2016-17 Answer all 14 questions (12 pages) Max. Marks: 41 For True/False questions, please provide a brief justification (1-2 sentences) for your answer.
More information10/17/ Gribble, Lazowska, Levy, Zahorjan 2. 10/17/ Gribble, Lazowska, Levy, Zahorjan 4
Temporal relations CSE 451: Operating Systems Autumn 2010 Module 7 Synchronization Instructions executed by a single thread are totally ordered A < B < C < Absent synchronization, instructions executed
More informationR13 SET - 1 2. Answering the question in Part-A is compulsory 1 a) Define Operating System. List out the objectives of an operating system. [3M] b) Describe different attributes of the process. [4M] c)
More informationSemaphores. Jinkyu Jeong Computer Systems Laboratory Sungkyunkwan University
Semaphores Jinkyu Jeong (jinkyu@skku.edu) Computer Systems Laboratory Sungkyunkwan University http://csl.skku.edu EEE3052: Introduction to Operating Systems, Fall 2017, Jinkyu Jeong (jinkyu@skku.edu) Synchronization
More informationCSE 120 Principles of Operating Systems
CSE 120 Principles of Operating Systems Spring 2018 Lecture 15: Multicore Geoffrey M. Voelker Multicore Operating Systems We have generally discussed operating systems concepts independent of the number
More informationCS 153 Design of Operating Systems Winter 2016
CS 153 Design of Operating Systems Winter 2016 Lecture 7: Synchronization Administrivia Homework 1 Due today by the end of day Hopefully you have started on project 1 by now? Kernel-level threads (preemptable
More informationProcess Management And Synchronization
Process Management And Synchronization In a single processor multiprogramming system the processor switches between the various jobs until to finish the execution of all jobs. These jobs will share the
More informationSynchronization I. Jo, Heeseung
Synchronization I Jo, Heeseung Today's Topics Synchronization problem Locks 2 Synchronization Threads cooperate in multithreaded programs To share resources, access shared data structures Also, to coordinate
More informationProblem Set 2. CS347: Operating Systems
CS347: Operating Systems Problem Set 2 1. Consider a clinic with one doctor and a very large waiting room (of infinite capacity). Any patient entering the clinic will wait in the waiting room until the
More informationInterprocess Communication By: Kaushik Vaghani
Interprocess Communication By: Kaushik Vaghani Background Race Condition: A situation where several processes access and manipulate the same data concurrently and the outcome of execution depends on the
More informationCS 162 Operating Systems and Systems Programming Professor: Anthony D. Joseph Spring Lecture 8: Semaphores, Monitors, & Condition Variables
CS 162 Operating Systems and Systems Programming Professor: Anthony D. Joseph Spring 2004 Lecture 8: Semaphores, Monitors, & Condition Variables 8.0 Main Points: Definition of semaphores Example of use
More informationCHAPTER 6: PROCESS SYNCHRONIZATION
CHAPTER 6: PROCESS SYNCHRONIZATION The slides do not contain all the information and cannot be treated as a study material for Operating System. Please refer the text book for exams. TOPICS Background
More informationMidterm Exam. October 20th, Thursday NSC
CSE 421/521 - Operating Systems Fall 2011 Lecture - XIV Midterm Review Tevfik Koşar University at Buffalo October 18 th, 2011 1 Midterm Exam October 20th, Thursday 9:30am-10:50am @215 NSC Chapters included
More informationCS 4410 Operating Systems. Review 1. Summer 2016 Cornell University
CS 4410 Operating Systems Review 1 Summer 2016 Cornell University 1 A modern computer system keyboard disks mouse printer monitor CPU Disk controller USB controller Graphics adapter memory OS device driver
More informationCase study: ext2 FS 1
Case study: ext2 FS 1 The ext2 file system Second Extended Filesystem The main Linux FS before ext3 Evolved from Minix filesystem (via Extended Filesystem ) Features Block size (1024, 2048, and 4096) configured
More informationConcurrent & Distributed Systems Supervision Exercises
Concurrent & Distributed Systems Supervision Exercises Stephen Kell Stephen.Kell@cl.cam.ac.uk November 9, 2009 These exercises are intended to cover all the main points of understanding in the lecture
More informationOperating Systems. Week 9 Recitation: Exam 2 Preview Review of Exam 2, Spring Paul Krzyzanowski. Rutgers University.
Operating Systems Week 9 Recitation: Exam 2 Preview Review of Exam 2, Spring 2014 Paul Krzyzanowski Rutgers University Spring 2015 March 27, 2015 2015 Paul Krzyzanowski 1 Exam 2 2012 Question 2a One of
More information1995 Paper 10 Question 7
995 Paper 0 Question 7 Why are multiple buffers often used between producing and consuming processes? Describe the operation of a semaphore. What is the difference between a counting semaphore and a binary
More informationChapter 6: Process Synchronization
Chapter 6: Process Synchronization Chapter 6: Synchronization 6.1 Background 6.2 The Critical-Section Problem 6.3 Peterson s Solution 6.4 Synchronization Hardware 6.5 Mutex Locks 6.6 Semaphores 6.7 Classic
More informationSemaphore. Originally called P() and V() wait (S) { while S <= 0 ; // no-op S--; } signal (S) { S++; }
Semaphore Semaphore S integer variable Two standard operations modify S: wait() and signal() Originally called P() and V() Can only be accessed via two indivisible (atomic) operations wait (S) { while
More informationDeadlock and Monitors. CS439: Principles of Computer Systems September 24, 2018
Deadlock and Monitors CS439: Principles of Computer Systems September 24, 2018 Bringing It All Together Processes Abstraction for protection Define address space Threads Share (and communicate) through
More informationOperating Systems Comprehensive Exam. Fall Student ID # 10/31/2013
Operating Systems Comprehensive Exam Fall 2013 Student ID # 10/31/2013 You must complete all of Section I You must complete two of the problems in Section II If you need more space to answer a question,
More informationCase study: ext2 FS 1
Case study: ext2 FS 1 The ext2 file system Second Extended Filesystem The main Linux FS before ext3 Evolved from Minix filesystem (via Extended Filesystem ) Features Block size (1024, 2048, and 4096) configured
More informationmode uid gid atime ctime mtime size block count reference count direct blocks (12) single indirect double indirect triple indirect mode uid gid atime
Recap: i-nodes Case study: ext FS The ext file system Second Extended Filesystem The main Linux FS before ext Evolved from Minix filesystem (via Extended Filesystem ) Features (4, 48, and 49) configured
More informationChapter 6: Synchronization. Operating System Concepts 8 th Edition,
Chapter 6: Synchronization, Silberschatz, Galvin and Gagne 2009 Outline Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Semaphores Classic Problems of Synchronization
More informationThreads. Threads The Thread Model (1) CSCE 351: Operating System Kernels Witawas Srisa-an Chapter 4-5
Threads CSCE 351: Operating System Kernels Witawas Srisa-an Chapter 4-5 1 Threads The Thread Model (1) (a) Three processes each with one thread (b) One process with three threads 2 1 The Thread Model (2)
More informationCPS 310 first midterm exam, 10/6/2014
CPS 310 first midterm exam, 10/6/2014 Your name please: Part 1. More fun with fork and exec* What is the output generated by this program? Please assume that each executed print statement completes, e.g.,
More informationSynchronization. CS61, Lecture 18. Prof. Stephen Chong November 3, 2011
Synchronization CS61, Lecture 18 Prof. Stephen Chong November 3, 2011 Announcements Assignment 5 Tell us your group by Sunday Nov 6 Due Thursday Nov 17 Talks of interest in next two days Towards Predictable,
More informationChapter 6: Process Synchronization
Chapter 6: Process Synchronization Objectives Introduce Concept of Critical-Section Problem Hardware and Software Solutions of Critical-Section Problem Concept of Atomic Transaction Operating Systems CS
More informationConcurrency. On multiprocessors, several threads can execute simultaneously, one on each processor.
Synchronization 1 Concurrency On multiprocessors, several threads can execute simultaneously, one on each processor. On uniprocessors, only one thread executes at a time. However, because of preemption
More informationC09: Process Synchronization
CISC 7310X C09: Process Synchronization Hui Chen Department of Computer & Information Science CUNY Brooklyn College 3/29/2018 CUNY Brooklyn College 1 Outline Race condition and critical regions The bounded
More informationChapter 6: Synchronization. Chapter 6: Synchronization. 6.1 Background. Part Three - Process Coordination. Consumer. Producer. 6.
Part Three - Process Coordination Chapter 6: Synchronization 6.1 Background Concurrent access to shared data may result in data inconsistency Maintaining data consistency requires mechanisms to ensure
More informationSynchronization. CSE 2431: Introduction to Operating Systems Reading: Chapter 5, [OSC] (except Section 5.10)
Synchronization CSE 2431: Introduction to Operating Systems Reading: Chapter 5, [OSC] (except Section 5.10) 1 Outline Critical region and mutual exclusion Mutual exclusion using busy waiting Sleep and
More informationOperating Systems Comprehensive Exam. Spring Student ID # 3/16/2006
Operating Systems Comprehensive Exam Spring 2006 Student ID # 3/16/2006 You must complete all of part I (60%) You must complete two of the three sections in part II (20% each) In Part I, circle or select
More informationOperating Systems ECE344
Operating Systems ECE344 Ding Yuan Announcement & Reminder Lab 0 mark posted on Piazza Great job! One problem: compilation error I fixed some for you this time, but won t do it next time Make sure you
More informationCSE 4/521 Introduction to Operating Systems. Lecture 24 I/O Systems (Overview, Application I/O Interface, Kernel I/O Subsystem) Summer 2018
CSE 4/521 Introduction to Operating Systems Lecture 24 I/O Systems (Overview, Application I/O Interface, Kernel I/O Subsystem) Summer 2018 Overview Objective: Explore the structure of an operating system
More informationSynchronization Principles
Synchronization Principles Gordon College Stephen Brinton The Problem with Concurrency Concurrent access to shared data may result in data inconsistency Maintaining data consistency requires mechanisms
More informationOperating Systems Comprehensive Exam. Spring Student ID # 3/20/2013
Operating Systems Comprehensive Exam Spring 2013 Student ID # 3/20/2013 You must complete all of Section I You must complete two of the problems in Section II If you need more space to answer a question,
More informationOperating Systems. Designed and Presented by Dr. Ayman Elshenawy Elsefy
Operating Systems Designed and Presented by Dr. Ayman Elshenawy Elsefy Dept. of Systems & Computer Eng.. AL-AZHAR University Website : eaymanelshenawy.wordpress.com Email : eaymanelshenawy@yahoo.com Reference
More informationFine-grained synchronization & lock-free data structures
Lecture 19: Fine-grained synchronization & lock-free data structures Parallel Computer Architecture and Programming Redo Exam statistics Example: a sorted linked list struct Node { int value; Node* next;
More informationSections 01 (11:30), 02 (16:00), 03 (8:30) Ashraf Aboulnaga & Borzoo Bonakdarpour
Course CS350 - Operating Systems Sections 01 (11:30), 02 (16:00), 03 (8:30) Instructor Ashraf Aboulnaga & Borzoo Bonakdarpour Date of Exam October 25, 2011 Time Period 19:00-21:00 Duration of Exam Number
More informationProcess Synchronization: Semaphores. CSSE 332 Operating Systems Rose-Hulman Institute of Technology
Process Synchronization: Semaphores CSSE 332 Operating Systems Rose-Hulman Institute of Technology Critical-section problem solution 1. Mutual Exclusion - If process Pi is executing in its critical section,
More informationCSE 153 Design of Operating Systems
CSE 153 Design of Operating Systems Winter 19 Lecture 7/8: Synchronization (1) Administrivia How is Lab going? Be prepared with questions for this weeks Lab My impression from TAs is that you are on track
More informationLecture 5: Synchronization w/locks
Lecture 5: Synchronization w/locks CSE 120: Principles of Operating Systems Alex C. Snoeren Lab 1 Due 10/19 Threads Are Made to Share Global variables and static objects are shared Stored in the static
More informationCOMP SCI 3SH3: Operating System Concepts (Term 2 Winter 2006) Test 2 February 27, 2006; Time: 50 Minutes ;. Questions Instructor: Dr.
COMP SCI 3SH3: Operating System Concepts (Term 2 Winter 2006) Test 2 February 27, 2006; Time: 50 Minutes ;. Questions Instructor: Dr. Kamran Sartipi Name: Student ID: Question 1 (Disk Block Allocation):
More informationCPSC/ECE 3220 Fall 2017 Exam Give the definition (note: not the roles) for an operating system as stated in the textbook. (2 pts.
CPSC/ECE 3220 Fall 2017 Exam 1 Name: 1. Give the definition (note: not the roles) for an operating system as stated in the textbook. (2 pts.) Referee / Illusionist / Glue. Circle only one of R, I, or G.
More informationFILE SYSTEMS, PART 2. CS124 Operating Systems Fall , Lecture 24
FILE SYSTEMS, PART 2 CS124 Operating Systems Fall 2017-2018, Lecture 24 2 Last Time: File Systems Introduced the concept of file systems Explored several ways of managing the contents of files Contiguous
More informationIV. Process Synchronisation
IV. Process Synchronisation Operating Systems Stefan Klinger Database & Information Systems Group University of Konstanz Summer Term 2009 Background Multiprogramming Multiple processes are executed asynchronously.
More informationCS 153 Design of Operating Systems Winter 2016
CS 153 Design of Operating Systems Winter 2016 Lecture 9: Semaphores and Monitors Some slides from Matt Welsh Summarize Where We Are Goal: Use mutual exclusion to protect critical sections of code that
More informationCS533 Concepts of Operating Systems. Jonathan Walpole
CS533 Concepts of Operating Systems Jonathan Walpole Introduction to Threads and Concurrency Why is Concurrency Important? Why study threads and concurrent programming in an OS class? What is a thread?
More informationOperating Systems Antonio Vivace revision 4 Licensed under GPLv3
Operating Systems Antonio Vivace - 2016 revision 4 Licensed under GPLv3 Process Synchronization Background A cooperating process can share directly a logical address space (code, data) or share data through
More informationSynchronization Spinlocks - Semaphores
CS 4410 Operating Systems Synchronization Spinlocks - Semaphores Summer 2013 Cornell University 1 Today How can I synchronize the execution of multiple threads of the same process? Example Race condition
More informationMore Types of Synchronization 11/29/16
More Types of Synchronization 11/29/16 Today s Agenda Classic thread patterns Other parallel programming patterns More synchronization primitives: RW locks Condition variables Semaphores Message passing
More informationChendu College of Engineering & Technology
Chendu College of Engineering & Technology (Approved by AICTE, New Delhi and Affiliated to Anna University) Zamin Endathur, Madurantakam, Kancheepuram District 603311 +91-44-27540091/92 www.ccet.org.in
More informationLearning Outcomes. Concurrency and Synchronisation. Textbook. Concurrency Example. Inter- Thread and Process Communication. Sections & 2.
Learning Outcomes Concurrency and Synchronisation Understand concurrency is an issue in operating systems and multithreaded applications Know the concept of a critical region. Understand how mutual exclusion
More informationLecture. DM510 - Operating Systems, Weekly Notes, Week 11/12, 2018
Lecture In the lecture on March 13 we will mainly discuss Chapter 6 (Process Scheduling). Examples will be be shown for the simulation of the Dining Philosopher problem, a solution with monitors will also
More informationConcurrency and Synchronisation
Concurrency and Synchronisation 1 Sections 2.3 & 2.4 Textbook 2 Making Single-Threaded Code Multithreaded Conflicts between threads over the use of a global variable 3 Inter- Thread and Process Communication
More informationConcurrency and Synchronisation
Concurrency and Synchronisation 1 Learning Outcomes Understand concurrency is an issue in operating systems and multithreaded applications Know the concept of a critical region. Understand how mutual exclusion
More informationFinal review. From threads to file systems
Final review q From threads to file systems Disclaimer Not guaranteed to be everything you need to know, just an overview of second half of the course 2 What s covered by the exam? Lectures from Threads
More informationCS 326 Operating Systems Synchronization. Greg Benson Department of Computer Science University of San Francisco
CS 326 Operating Systems Synchronization Greg Benson Department of Computer Science University of San Francisco High-level Synchronization So far we have seen low-level mechanisms for synchronization (mutual
More informationMultiprocessor System. Multiprocessor Systems. Bus Based UMA. Types of Multiprocessors (MPs) Cache Consistency. Bus Based UMA. Chapter 8, 8.
Multiprocessor System Multiprocessor Systems Chapter 8, 8.1 We will look at shared-memory multiprocessors More than one processor sharing the same memory A single CPU can only go so fast Use more than
More informationReminder from last time
Concurrent systems Lecture 2: More mutual exclusion, semaphores, and producer-consumer relationships DrRobert N. M. Watson 1 Reminder from last time Definition of a concurrent system Origins of concurrency
More informationCS370 Operating Systems
CS370 Operating Systems Colorado State University Yashwant K Malaiya Spring 1018 L11 Synchronization Slides based on Text by Silberschatz, Galvin, Gagne Various sources 1 1 FAQ Multilevel feedback queue:
More informationDeadlock and Monitors. CS439: Principles of Computer Systems February 7, 2018
Deadlock and Monitors CS439: Principles of Computer Systems February 7, 2018 Last Time Terminology Safety and liveness Atomic Instructions, Synchronization, Mutual Exclusion, Critical Sections Synchronization
More informationInterprocess Communication and Synchronization
Chapter 2 (Second Part) Interprocess Communication and Synchronization Slide Credits: Jonathan Walpole Andrew Tanenbaum 1 Outline Race Conditions Mutual Exclusion and Critical Regions Mutex s Test-And-Set
More informationReview: Processes. A process is an instance of a running program. POSIX Thread APIs:
Review: Processes A process is an instance of a running program - A thread is an execution context - Process can have one or more threads - Threads share address space (code, data, heap), open files -
More informationCS 4284 Systems Capstone
CS 4284 Systems Capstone Disks & File Systems Godmar Back Disks & Filesystems Disk Schematics Source: Micro House PC Hardware Library Volume I: Hard Drives 3 Tracks, Sectors, Cylinders 4 Hard Disk Example
More informationConcept of a process
Concept of a process In the context of this course a process is a program whose execution is in progress States of a process: running, ready, blocked Submit Ready Running Completion Blocked Concurrent
More informationCLOUD-SCALE FILE SYSTEMS
Data Management in the Cloud CLOUD-SCALE FILE SYSTEMS 92 Google File System (GFS) Designing a file system for the Cloud design assumptions design choices Architecture GFS Master GFS Chunkservers GFS Clients
More informationSynchronization I. Jin-Soo Kim Computer Systems Laboratory Sungkyunkwan University
Synchronization I Jin-Soo Kim (jinsookim@skku.edu) Computer Systems Laboratory Sungkyunkwan University http://csl.skku.edu Today s Topics Synchronization problem Locks 2 Synchronization Threads cooperate
More informationMultiprocessor Systems. COMP s1
Multiprocessor Systems 1 Multiprocessor System We will look at shared-memory multiprocessors More than one processor sharing the same memory A single CPU can only go so fast Use more than one CPU to improve
More informationProgramming Languages
TECHNISCHE UNIVERSITÄT MÜNCHEN FAKULTÄT FÜR INFORMATIK Programming Languages Concurrency: Atomic Executions, Locks and Monitors Dr. Michael Petter Winter term 2016 Atomic Executions, Locks and Monitors
More informationOpera&ng Systems ECE344
Opera&ng Systems ECE344 Lecture 6: Synchroniza&on (II) Semaphores and Monitors Ding Yuan Higher- Level Synchroniza&on We looked at using locks to provide mutual exclusion Locks work, but they have some
More informationOperating Systems Comprehensive Exam. Spring Student ID # 2/17/2011
Operating Systems Comprehensive Exam Spring 2011 Student ID # 2/17/2011 You must complete all of Section I You must complete two of the problems in Section II If you need more space to answer a question,
More informationThis is an open book, open notes exam. But no online or in-class chatting.
Principles of Operating Systems Fall 2017 Final 12/13/2017 Time Limit: 8:00am - 10:00am Name (Print): Don t forget to write your name on this exam. This is an open book, open notes exam. But no online
More informationMid-term Roll no: Scheduler Activations: Effective Kernel Support for the User-Level Management of Parallelism
Advanced Operating Systems Spring 2013 Mid-term Roll no: Instructions. The exam consists of 30 multiple choice questions, each worth one mark. You have 2 hours and 30 minutes to solve this. If you think
More informationOperating Systems. Operating Systems Summer 2017 Sina Meraji U of T
Operating Systems Operating Systems Summer 2017 Sina Meraji U of T More Special Instructions Swap (or Exchange) instruction Operates on two words atomically Can also be used to solve critical section problem
More informationName: Instructions. Problem 1 : Short answer. [48 points] CMU / Storage Systems 20 April 2011 Spring 2011 Exam 2
CMU 18-746/15-746 Storage Systems 20 April 2011 Spring 2011 Exam 2 Instructions Name: There are four (4) questions on the exam. You may find questions that could have several answers and require an explanation
More informationDepartment of Electrical Engineering and Computer Science MASSACHUSETTS INSTITUTE OF TECHNOLOGY Fall 2010.
Department of Electrical Engineering and Computer Science MASSACHUSETTS INSTITUTE OF TECHNOLOGY 6.828 Fall 2010 Quiz II Solutions Mean 85 Median 89 Std. dev 11.09 20 15 10 5 0 0 10 20 30 40 50 60 70 80
More informationSynchronization 1. Synchronization
Synchronization 1 Synchronization key concepts critical sections, mutual exclusion, test-and-set, spinlocks, blocking and blocking locks, semaphores, condition variables, deadlocks reading Three Easy Pieces:
More informationCS-537: Midterm Exam (Spring 2001)
CS-537: Midterm Exam (Spring 2001) Please Read All Questions Carefully! There are seven (7) total numbered pages Name: 1 Grading Page Points Total Possible Part I: Short Answers (12 5) 60 Part II: Long
More informationKernel Range Reader/Writer Locking
Kernel Range Reader/Writer Locking Linux Plumbers Conference September 2017. Los Angeles, CA. Davidlohr Bueso SUSE Labs. Agenda 1. Introduction 2. Semantics 3. Range lock vs rw_semaphore
More informationChapter 6: Process Synchronization. Module 6: Process Synchronization
Chapter 6: Process Synchronization Module 6: Process Synchronization Background The Critical-Section Problem Peterson s Solution Synchronization Hardware Semaphores Classic Problems of Synchronization
More informationSynchronization. CISC3595/5595 Fall 2015 Fordham Univ.
Synchronization CISC3595/5595 Fall 2015 Fordham Univ. Synchronization Motivation When threads concurrently read/write shared memory, program behavior is undefined Two threads write to the same variable;
More informationCSE Traditional Operating Systems deal with typical system software designed to be:
CSE 6431 Traditional Operating Systems deal with typical system software designed to be: general purpose running on single processor machines Advanced Operating Systems are designed for either a special
More informationLecture Topics. Announcements. Today: Concurrency (Stallings, chapter , 5.7) Next: Exam #1. Self-Study Exercise #5. Project #3 (due 9/28)
Lecture Topics Today: Concurrency (Stallings, chapter 5.1-5.4, 5.7) Next: Exam #1 1 Announcements Self-Study Exercise #5 Project #3 (due 9/28) Project #4 (due 10/12) 2 Exam #1 Tuesday, 10/3 during lecture
More informationCS3210: Coordination. Tim Andersen
1 CS3210: Coordination Tim Andersen 2 Administrivia Lab5 out, due November 21st Demo day: 8 min for demo, 2 min for Q&A Final project (write up): December 2nd 3 Today's plan Context switching (i.e., swtch
More informationOperating Systems Design Exam 2 Review: Fall 2010
Operating Systems Design Exam 2 Review: Fall 2010 Paul Krzyzanowski pxk@cs.rutgers.edu 1 1. Why could adding more memory to a computer make it run faster? If processes don t have their working sets in
More informationMonitors; Software Transactional Memory
Monitors; Software Transactional Memory Parallel and Distributed Computing Department of Computer Science and Engineering (DEI) Instituto Superior Técnico March 17, 2016 CPD (DEI / IST) Parallel and Distributed
More informationOperating Systems Design Exam 2 Review: Spring 2011
Operating Systems Design Exam 2 Review: Spring 2011 Paul Krzyzanowski pxk@cs.rutgers.edu 1 Question 1 CPU utilization tends to be lower when: a. There are more processes in memory. b. There are fewer processes
More information